1. Field of the Invention
The invention relates to a signal correction circuit for correcting deviating pixel values. Such a circuit is used, for example, for correcting CCD sensors, some pixels of which have a dark current which is larger than average. Particularly in sensors having many pixels, there is a great risk of drop out of one or more pixels having a deviating dark current.
2. Description of the Related Art
A signal correction circuit of this type is described in the article by B. Botte, "Digital automatic pixel correction in new generation CCD broadcast cameras", presented at the IBC 1992, pp. 474-478. In this circuit, a correction signal is corrected for the sensor temperature. To this end, the address of the faulty pixel should be known and, together with the magnitude of the correction, it should be stored in a memory. This circuit has the following drawbacks. The circuit is not flexible; if, in fact, new defects occur, the contents of the memory must be adapted. The temperature behavior is probably not so predictable so that the corrections are not complete. Moreover, the dark current of the pixels may vary with respect to time with a too large dark current or even become normal. Then, there will be erroneous corrections.